Prior art which is related to this technical field can e.g. be found by the technical specifications TS 36.300 (current version: 10.0.0), TS 36.401 (current version 9.2.0), TS 36.420 (current version 9.0.0), and TS 36.423 (current version: 9.3.0) of the 3GPP.
The following meanings for the abbreviations used in this specification apply:
3G: 3rd Generation
3GPP: 3rd Generation Partnership Project
ANR: Automatic Neighborhood Relation
AP: Application Protocol
CN: Core Network
CSG: Closed Subscriber Group
DL: Downlink
DSR: Detected Set Reporting
eNB: evolved Node B (eNode B)
HeNB: Home eNB
HII: High Interference Indication
HO: Hand-over
ID: Identifier
IOI: Interference Overload Indication
IP: Internet Protocol
IE: Information Element
LTE: Long Term Evolution
LTE-A: Long Term Evolution Advanced
MNO: Mobile Network Operator
NCL: Neighboring Cell List
NLM: Network Listening Mode
UE: User Equipment
UL: Uplink
In the field of to LTE/LTE-A and femtocells the enterprise usage of HeNBs and in particular their auto-configuration like Automated Neighborhood Relation (ANR) has recently become the target of intense consideration. It is assumed that HeNBs in enterprises will generate a high portion of revenues related to the concept of femtocells. Hence, the 3GPP and the “Femtoforum” experience many activities towards enhancements in a dense femtocell deployment in an enterprise scenario.
However, one problem observed in enterprise femtocell deployment relates to cases of a massive femtocell roll-out where each base station has to have a configuration of Neighbouring Cell List (NCL) for HO purposes. Nowadays this is done manually and often tuned for better performance via e.g. drive-test over long and repetitive live network measurements and off-line processing. In this connection a rather high amount of tedious work, time and money is needed for proper NCL configuration in enterprise scenario especially taking into account the foreseen number of HeNBs to be deployed.
Hence, an automated, quick and reliable NCL population method is urgently needed.
A possible solution to NCL population in 3G is to enable Detected Set Reporting (DSR). As studies have shown (see “Neighbor Cell Relation List and Physical Cell Identity Self-Organization in LTE”, M. Amirijoo, F. Gunnarsson, H. Kallin, J. Moe, K. Zetterberg, Ericsson Research, ICC 2008 workshop proceedings, 2008; and “Self-optimizing Neighbor Cell List for UTRA FDD Networks Using Detected Set Reporting”, D. Soldani, I. Ore, Nokia Networks, IEEE, 2007), this has several drawbacks like e.g. initial high number of measurements to be taken, high signaling load due to frequent measurements, lower UE battery life and several failed HO attempts before the actual configuration final set-up. The same principles may apply to LTE ANR which may be time and resources consuming, taking into account that femto overlapping areas are quite small. Hence, users may relatively quickly and often move from one cell to another.